Shading devices, such as blinds, are used in a variety of commercial and household applications to keep excessive light and heat out of building structures, such as for example office buildings. Usually, shading devices are mounted either interior or exterior of windows or between the window panes and are controllable so that the amount of sunlight entering the building can be adjusted manually or using a suitable controlling system.
Automatic controlling systems are known in the art, which control shading devices according to one or more measured environmental parameters, such as daylight conditions, wind or according to global building control settings or user preferences. Document WO 2008/149285 A1 discloses a controllable window blind having multiple slats, in which a tilt angle of said slats is controlled in response to the detected interior light intensity.
However, a problem exists because even when the interior light intensity is suitably controlled, it may nevertheless be possible that direct light, e.g. sunlight, is transmitted through a shading device, which may cause overheating or glare on work desks and other specular surfaces, such as computer monitors, resulting in a substantial disturbance or discomfort, especially in office environments.
It is therefore an object of the present invention to provide a system for controlling a shading device, which reduces direct sunlight transmission and enhances thermal comfort and lighting conditions.